Autoantibodies Against the High Affinity IgE Receptor (FcεR1α) are Equally Prevalent in Patients with Auto-Immune Thyroid Disease, Chronic Idiopathic Urticaria and Controls

Abstract

RATIONALE: Chronic idiopathic urticaria (CIU) is characterized by hives of uncertain etiology of >6 weeks duration. Investigators have identified auto-antibodies directed against the high affinity IgE receptor alpha chain (FcεR1α) on mast cells in many of these patients. Approximately 30% of patients with CIU also have autoimmune thyroiditis. The aim of this study was to determine the incidence of FcεR1α auto-antibodies in patients with CIU, Hashimoto's thyroiditis, and control groups and to correlate their presence with positive autologous serum skin testing (ASST) and autoimmune thyroiditis.METHODS: Individuals with Hashimoto's thyroiditis (n = 10), CIU (n = 18) and controls (n = 22) were enrolled into the study. All subjects had blood drawn and evaluated for TSH, free T4 (if TSH abnormal) and thyroid auto-antibodies. All patients underwent ASST and had serum screened for the presence of anti-FcεR1α antibodies by ELISA.RESULTS: We developed and validated our ability to reproducibly quantify anti-FcεR1α antibodies. However, no statistically significant differences in the incidence of anti-FcεR1α antibodies were identified between control patients (33%) and patients with CIU (35%), Hashimoto's (30%) or patients with both CIU and Hashimoto's (35%). Anti-thyroid antibodies were present in 18% of controls and 44% of CIU patients. The ASST was positive in 22% of controls and in 60% of CIU patients. The prevalence of anti-thyroid antibodies did not differ between CIU patients with and without ASST.CONCLUSIONS: Anti-FcεR1α antibodies are equally prevalent in control, Hashimoto's and CIU subjects. ASST positivity does not correlate with the presence of anti-thyroid antibodies. RATIONALE: Chronic idiopathic urticaria (CIU) is characterized by hives of uncertain etiology of >6 weeks duration. Investigators have identified auto-antibodies directed against the high affinity IgE receptor alpha chain (FcεR1α) on mast cells in many of these patients. Approximately 30% of patients with CIU also have autoimmune thyroiditis. The aim of this study was to determine the incidence of FcεR1α auto-antibodies in patients with CIU, Hashimoto's thyroiditis, and control groups and to correlate their presence with positive autologous serum skin testing (ASST) and autoimmune thyroiditis. METHODS: Individuals with Hashimoto's thyroiditis (n = 10), CIU (n = 18) and controls (n = 22) were enrolled into the study. All subjects had blood drawn and evaluated for TSH, free T4 (if TSH abnormal) and thyroid auto-antibodies. All patients underwent ASST and had serum screened for the presence of anti-FcεR1α antibodies by ELISA. RESULTS: We developed and validated our ability to reproducibly quantify anti-FcεR1α antibodies. However, no statistically significant differences in the incidence of anti-FcεR1α antibodies were identified between control patients (33%) and patients with CIU (35%), Hashimoto's (30%) or patients with both CIU and Hashimoto's (35%). Anti-thyroid antibodies were present in 18% of controls and 44% of CIU patients. The ASST was positive in 22% of controls and in 60% of CIU patients. The prevalence of anti-thyroid antibodies did not differ between CIU patients with and without ASST. CONCLUSIONS: Anti-FcεR1α antibodies are equally prevalent in control, Hashimoto's and CIU subjects. ASST positivity does not correlate with the presence of anti-thyroid antibodies.